UFC 3-280-03
23 JULY 2003
conditioning chemicals, the cost and volume increase may not be warranted versus the
increase in the dewatering results.
2-4.5
Filter Press Major Equipment Components. The major components of the
filter press are the frame, plates, filter cloth, hydraulic plate closing mechanism, and
plate shifting mechanism. A schematic showing the major components of the recessed
filter press system is shown in Figure 2-7.
2-4.5.1 Structural Frame. The structural frame of a recessed filter press consists of
a fixed end, a moving end, and plate support systems (EPA 1986). The fixed end
anchors one end of the filter press and plate support bars. The moving end anchors the
opposite end of the press and houses the plate closing mechanism. The plate support
bars span between these two ends and carry the filter press plates.
Two typical configurations of the plate support system are a side bar or an
overhead bar. A diagram of each of these is shown in Figure 2-7. The side bar
configuration consists of two side bars that provide support at each side of the plate at a
point slightly above the center of each plate. The overhead bar configuration consists of
two overhead bars and two lower tie bars. The plates in the overhead assembly are
attached to a support beam and carriage assembly at the center of each plate. The side
bar frame is normally used for presses with plates up to 1200 mm (48 inches) and with
pressures up to 1550 kPa (225 psi). Overhead frames are used for larger plates (i.e.,
1500 mm [60 inch] plates and up) or pressures greater than 1550 kPa (225 psi), such
as in the variable-volume presses. The advantage of the side bar support system is that
it allows for easy removal of individual plates directly from the press, whereas the
advantage of the overhead type support allows easier observation between individual
plates. Problems or disadvantages associated with the side bar support system are
jamming of the plate shifting mechanism and access to plates during sludge cake dis-
charging operations. However, the initial cost for this type of system is less than the
overhead bar assembly.
2-4.5.2 Filter Press Plates. Filter press plates are available in several types,
construction, dimensions, and materials (WEF 1992). The most common type, recessed
plates, are fabricated with a constant recess (or depths) and area on adjacent plates in
which the constant volume filter cake forms. To provide additional support and prevent
deflection of the plates in the recessed area, the plates normally are constructed with
stay bosses within them. The stay bosses have the same overall thickness as the
perimeter of the plate. The number and size of the stay bosses primarily depend on the
dimensions and structural material of the plate.
2-4.5.2.1 Filter press plates range in size (i.e., 600 to 2100 mm [24 to 84 inches]) and
can be round, square, or rectangular. Depending on the plate design and the desired
cake thickness, the recessed area can also range from 25 to 50 mm (1 to 2 inches) in
thickness, with 32 mm (1.25 inches) being typical. Plates are typically constructed with a
center feed port, with filtrate ports located at the corners of the recessed area. Although
corner feed plates, which use one or more corner ports for sludge feed, may be required
for specialty applications, these types of plates are typically avoided because foreign
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